The invention relates generally to electromechanical devices, and more specifically to a library for storing cartridges of data-storage media, such as magnetic tape, and for providing read/write access to the stored media.
Because today""s computer users often store large volumes of information on computer systems, it has become increasingly more important to backup this information to non-volatile storage media, such as magnetic tape or CD-ROM (Compact-Disc Read-Only Memory), and to archive this media so that the stored information can be easily retrieved. Furthermore, as the amount of a user""s backed-up data increases, he often archives the storage media with the aid of a computer to reduce inventory errors or other errors that may occur when the storage media are manually archived.
One type of device that is often used to archive data-storage media is a data storage library. Typically, the library is interfaced to a host computer system, and includes a media drive for reading data from and writing data to the storage media, a section for archiving the storage media, a section where an operator can load and unload the storage media, and a mechanism for transporting the storage media among the load/unload section, the archive section, and the drive. By communicating with or controlling the library, the host computer system can keep track of the specific information stored on a particular storage medium and where in the library the particular storage medium is located. Thus, when one wishes to retrieve specific archived information, the host computer can control the transport mechanism to retrieve the storage medium containing the specific information and to insert the storage medium into the media drive so that the computer can access the information.
A problem with such data storage libraries is that the on-board transport mechanism often requires a relatively large operating space, and thus significantly reduces the amount of space available for media storage.
Furthermore, in today""s highly computerized environment, there are many interface protocols and formats, including SCSI, fiber-channel, and ultra-wide interfaces. Therefore, a manufacturer often must make costly and complex modifications to a library so that it can properly interface with a customer""s computer system. Alternatively, the manufacturer can produce different versions of the library, one version for each interface protocol and format. But this also significantly increases overall manufacturing costs.
Additionally, many computer users want a storage library to be rack-mountable so that it can be used to archive information from an entire computer network. But many libraries cannot be rack mounted because they are not properly sized to fit within the standard rack space or because parts of the library, such as an open door, will encroach on the rack space occupied by a component mounted next to the library. Furthermore, many of the libraries that are rack-mountable use the allotted rack space inefficiently. For example, such libraries may utilize the full width of the rack space but not the full depth. Moreover, many users want the storage library to be mountable within a fraction of a standard rack width but to still have a relatively large information storage capacity.
In one aspect of the invention, a library is provided for storing a cartridge of data-storage media. The library includes a removable module and a chassis having a module receptacle. Cartridge storage slots are disposed within the chassis, and a media drive is disposed within the removable module. A cartridge transporter is disposed within the chassis and transports the cartridge between one of the cartridge slots and the media drive when the module is inserted within the module receptacle. A library control circuit is disposed within the chassis and controls the cartridge transporter. An interface circuit is disposed within the removable module and electronically interfaces a host computer to the media drive, and, when the removable module is inserted within the module receptacle of the chassis, electronically interfaces the computer to the library control circuit.
Because the interface circuitry is mounted on a removable module, a library can be quickly and easily customized by inserting a module that provides the interface used by the customer""s host computer or computer network. Furthermore, only one version of the base library unit, i.e., the chassis and the components mounted within the chassis, need be manufactured. This significantly reduces the cost and complexity of the manufacturing process.